problem solved

So ... if you know there was a notice left for the package, presumably you used DC?

If it was DC purchased from PBS, then you already have the credits for the package. If you didn't purchase the DC from PBS, and the other member won't respond to your message, then wait until the books get marked lost in the mail by PBS, and then contact them and ask them to look into the other account. If the other account looks like it is inactive, they may be able to credit you for the books.

What Sara said.  If you did use PBS DC, and the tracking shows delivered but the other member is non-responsive, you can still point it out to PBS admin.  They might wish to watch for more evidence of an inactive account.

IIRC the PO will hold the package 14 days before returning, most members will pick it up within that time frame.  Have you checked the address to see if it's in Storm Sandy's wake?  Some of those members are still experiencing mail delays and home dislocation.